It is known to excavate earth so as to build a structure in the excavation site, or to remove contaminated earth, among other reasons. Before these excavations can occur, however, measures must be taken to secure or “retain” the earth that is adjacent to the excavation site so as to prevent this earth from sliding into the site, interrupting work, and/or other undesirable drawbacks. One such measure used to secure the earth is a retaining wall, which is installed to prevent earth from moving from an area where it is retained, to an area where there is no earth (i.e. the excavated site).
Typically, a retaining wall is a vertically-erected or laterally-stepped wall having one side facing the excavated site, and another side holding back the earth from the site. Multiple retaining walls can be erected around the site, depending on its configuration and requirements. Retaining walls can also be used for preventing fluid from entering an area, such as when used to form the walls of a cofferdam, or to seal or contain a landfill sight, for example.
Once a retaining wall is in place, the forces acting on it, and that it must resist, are the mass of the earth being retained, the mass of any matter on top of the wall, the moment force generated by the earth about the point at which the wall is in the ground. Other forces may also act against the wall (i.e., earth tremors, traffic loads, local vibrational loads, etc.). In known retaining walls, these forces are resisted by the inertial mass of the wall and the friction generated by the soil against the wall. Therefore, the retaining wall must resist both horizontal displacement and rotational moment forces.
Different types of retaining walls, and methods for creating them, are known in the art.
For example, retaining walls formed of sheet piles are known. Sheet piles are typically corrugated sheets of metal, although wood and other material can be used, which interlock or are assembled together to form a retaining wall. Generally speaking, sheet piles must be driven into the earth with an appropriate driving device to a depth that extends far below the final excavation depth when not anchored. A portion of the sheet piles are generally left sticking out of the ground. Once driven into the ground, excavation of the area can occur. Some of the disadvantages associated with the use of sheet piles for creating retaining walls include: a) sheet piles need to be banged or driven into the ground, which can create much noise and prevent the installation of the retaining wall at night due to noise constraints; b) sheet piles are not often self-sustainable or suitable for use in wide or deep retaining walls; c) they do not often provide enough space to insert an anchor when the sheet piles are in the ground and adjacent structures are present on both sides; d) sheet piles often cannot be driven past underground hard rock formations, which means these formations must be broken up by drilling, increasing installation times and costs even more; e) sheet piles are not often suitable for sites in dense urban areas, where there is a need to avoid disturbing the earth near the foundations of adjacent buildings; f) they are not often ideal for forming impervious barriers because there is the possibility of leaking at the junction of sheet piles and corrosion may destroy metal continuity; g) etc.
Also known are retaining walls known as “Berlin” walls or soldier pile walls. These retaining walls are typically formed by driving soldier piles (essentially concrete or steel cylinders or H beams and/or planks) into the ground at regular intervals. Then, excavation is performed to very small depths. Afterwards, the soldier piles are then linked by webbing or lagging, which typically consists of wood or concrete panels, and which holds back the earth from the excavated area. Some of the disadvantages of retaining walls made of soldier piles and/or Berlin walls include: i) they are primarily limited to temporary constructions; ii) as with sheet piles, they are not suitable for being used as an impervious barrier; iii) lagging made of wood can often rot in wet earths over time, thus reducing the ability of the wall to retain earths and potentially generate hazardous bacteria; iv) as with the sheet piles, the driving of the soldier piles can create much noise; v) they require beams and anchors to ensure their stability and may interfere with the building layout; vi) etc.
Another known type of retaining wall includes those made of concrete. U.S. Pat. No. 4,818,142 to COCHRAN relates to a method and apparatus of constructing a walled pool excavation. A method and apparatus are described for forming a cementitious walled ground excavation for receiving a pool.
US patent application US 2011/0142550 A1 to LEE relates to a method for constructing a chair-type, self-supported earth retaining wall. The document describes a method for constructing a chair-type, self-supported earth retaining wall used for retaining external forces such as earth pressure prior to an excavation. A flowable stiffening material is also described.
The following US patent documents also relate to retaining walls and methods for constructing retaining walls or other similar structures: U.S. Pat. No. 7,114,887 B1; U.S. Pat. No. 5,193,324; U.S. Pat. No. 3,898,844; and U.S. Pat. No. 1,650,827.
The following foreign patent documents are also known: JP 2005207144 A; JP 2005155094 A; JP 2001226968 A; JP 10131175 A; JP 06081354 A; JP 04336117 A; JP 02164937 A; JP 60173223 A; JP 60173214 A; and CN 101139838 A.
Some disadvantages associated some of these known retaining walls and methods include: I) they often require very large machinery to prepare the earth for the retaining wall, which can hinder the ability to create a retaining wall on sites more limited workspace; II) the retaining walls so constructed are often relatively thin structures because of the need to minimize the use of concrete or other materials, resulting in additional reinforcement and anchoring being necessary which complicates the construction; III) such walls may not be sufficiently strong to support other structures, vehicles, or equipment; d) etc.
Hence, in light of the aforementioned, there is a need for a method and retaining wall which, by virtue of its steps, design and components, would be able to overcome or at least minimize some of the aforementioned prior art problems.